The present invention relates to a solar water heater.
Solar water heaters are known which comprise a heat collector of the heat pipe type and a hot water tank. Because the condenser portion of the collector is held in contact with the bottom metal plate of the tank or inserted in the tank, the conventional solar water heater has the problem that a heat loss is liable to occur owing to the release of heat from the collector during night when no solar heat is available. Further with the conventional heater, a heat collector unit having the collector and a hot water storage unit including the tank are in the form of an integral assembly which has such a peculiar shape that the storage unit is projected upward from the rear end of a case. Additionally, the heater, which is heavy, is not balanced in weight since the storage unit is heavier. Thus, the heater is cumbersome to handle or treat and is not easy to package and transport. When such heaters are arranged as stacked up for storage, useless spaces occur to necessitate a large space for storage. The heater has another problem in that when water leaks from the tank or other portion, the heater must be repaired by a very cumbersome procedure because it has an integral structure.
An indirect solar water heater is also known which comprises a solar heat collector placed on the roof for heating an antifreeze solution or like heating medium, and a hot water tank having a radiator and disposed under the roof for heating water with the hot heating medium passed through the radiator. The collector comprises collector tubes having fins and arranged in parallel for passing the heating medium therethrough, and a pair of headers connected to opposite ends of the collector tubes. With this collector, however, the collector tubes including the fins and the headers are liable to release heat from the surface during night when no solar heat is available, consequently cooling the medium and resulting in a great heat loss. Thus, the heater of this type is inefficient. Moreover, the collector is not easy to fabricate because there are many weld joints between the headers and the collector tubes, while the collector is susceptible to leakage, for example, due to improper welding. It is cumbersome to repair when a leak develops. The collector is further inefficient since solar heat is not collected by the pair of header portions, while the collector is not compact owing to the presence of the headers.